Various methods have been employed to electronically control water flow through a water control device such as a faucet or spigot. Among the accepted methods is the use of an optical sensor typically employed in combination with an infrared (“IR”) source or IR emitter that together with processing electronics, are used to control a solenoid valve. Generally speaking, a pulsed IR beam is reflected from an object (such as a user's hands or other body parts, for example) and sensed by a photo detector to determine whether to activate or deactivate the solenoid valve. Pulsed IR sensing remains at the forefront of sensing techniques used with these types of devices, due in part to its reasonable performance and low cost. Automatic water flow control devices incorporating pulsed IR technology do, however, have a number of shortcomings.
A common denominator for many of the problems associated with automatically activated flow control devices, such as faucets, is the environment in which such devices are installed and operate. For instance, existing IR sensor designs generally suffer from an inability to adapt to changes in the background signal level associated with a gradual discoloration of the sink in which the faucet is mounted, a gradual degradation of the sensor lens due to the use of abrasive cleaning compounds, a gradual degradation of the IR emitter performance, among other things. Generally, existing sensors employ a fixed sensitivity threshold that is set either at the factory or by the installer (or both). When the IR sensor sensitivity is fixed, the sensors performance will inevitably degrade with environmental changes, and when the degradation causes faulty operation, a service call may be required. In some instances, the gradual degradation will go unnoticed resulting in poor performance.
In addition, IR sensors of the type made integral with the faucet often detect reflections from the water stream dispensed from the faucet. When the IR emitter is mounted behind the aerator of the faucet, as is commonly done in the art, near-IR light is reflected back from the water stream to the IR receiver causing the water to remain on, which results in a waste of water and annoyance to the user. In such a reflection scenario, the solenoid valve does not usually deactivate until the electronics of the device causes the faucet to “time out”.
Inconsistent lighting conditions, as well as water and/or soap film deposits on the optical lens of the IR sensors also cause faulty operation of an automatic flow device, such as a faucet or other device activated via IR sensing. In addition, paper towels or other debris left in the sink basin can induce misleading reflections to the IR receiver.
Servicing and maintenance of presently available automatically activated flow control devices are often burdensome and time-consuming tasks. Such tasks prove particularly burdensome for maintenance personnel in settings such as public restrooms where there are a number of automatically activated flow control devices, such as faucets or toilets, in a single room. Typically to test such flow control devices, each flow control device is manually activated to enable determination of whether or not it is malfunctioning. Moreover, calibration, recalibration, and most repair work to individual units presently require maintenance personnel to at least partially disassemble or at least manually access the electronics of the units to facilitate repair work. Such tasks may be time consuming and difficult to accomplish given the location of the device electronics (usually beneath, behind or under the counter top, toilet, or other structure supporting the device). Likewise, updating or enhancing the software or electronics of these devices usually requires maintenance personnel to access the device electronics.
In addition, calibration of today's automatically activated flow control devices is often labor intensive and inefficient with respect to devices presently on the market. The low cost IR sensing devices employed in automatically activated flow control devices vary with respect to power requirements, performance, and other criteria. As a result, readings taken by these IR sensing units (such as whether a user's hands are present beneath the aerator of a faucet) are generally non-uniform from device to device and, therefore, often result in improper activation and deactivation of some devices. Similarly, as battery power for these devices decreases over time, so does the power output of the IR sensing devices. As a result, manual calibration of conventional automatically activated flow control devices is generally required during initial installation, and thereafter on a frequent basis following extended periods of use.
Unfortunately, vandalism and water damage also adversely affect the use and proper operation of automatically activated flow control devices presently available in the art. Water often travels along the wiring harness extending from the flow control device to the device's electronics causing corrosion to the parts. On occasion, vandals may attempt to break into the electronics box associated with the device or pull the wires from either the electronics box or the faucet.